This invention relates to hand-held, multiple use tools and more particularly to a tool having a retractable, sliding-blade knife at one end of a handle and a pair of special-purpose wheels rotatably mounted at a second end of the handle.
The installation of screening material into the frames of window and door screens and the like involves hand labor by screen installers. In most cases, the skilled screen installers use three hand tools respectively in sequence. A knife is used to cut the screen to a size larger than the opening. The cut piece of screen is laid over the frame, covering the opening. A wheel having a convex edge small enough to fit within the screen-holding groove in the frame, rotatably mounted on a handle is used to press the screen into the groove. A wheel having a concave edge adapted to fit over a resilient locking bead or spline is then used to force the spline into the groove over the screen to lock the screen in place on the frame, taut and wrinkle-free over the opening. This wheel is also rotatably mounted on handle. Considerable force must often be used to deform the spline to fit into the groove and pull the screen taut. Having a concave edge on the wheel helps to hold the spline in place while force is applied. A knife is then used to trim excess screen from beyond the groove.
Screen installing tools comprising a handle with a concave edge wheel rotatably mounted at one end of a handle and a convex wheel at another end are well known in the art. This structure requires the worker to turn the tool end for end if he uses the same stroke for both wheels. He must lay this tool aside and pick up a knife whenever he must cut the screen. This is awkward and time consuming.
U.S. Pat. No. 4,910,821 issued 3/27/90 to Kieferie discloses a screen installer's tool having a handle with a retractable sliding-blade knife at one end of a handle and a convex wheel rotatably mounted at another end. The installer must use the single wheel both for forcing the screen into the groove, for which it is well suited, and for forcing the locking bead or spline into the groove, for which it is not well suited, since it does not engage the spline as effectively as a concave edge. Greater skill and care is required of the worker. An indentation in the handle is required to enhance gripping during forceful pressure on the spline.
In the hand fabrication of cardboard and corrugated paperboard boxes, one ordinarily traces a pattern on the flat sheet material. The pattern includes the cut to be made along the outer perimeter and the lines along which folds are to be made. The cuts are made with a knife. The folds are effectively made by first running a rotary wheel with a convex edge along each line to indent the material to facilitate folding along the line. Tracing a pattern through a thin sheet material such as paper or plastic is easily done with a pounce wheel rotatably mounted on a handle. A pounce wheel is a disc with pin-wheel projections extending radially from the periphery of the disc. The pins go through the pattern, putting a row of pin holes in the sheet without cutting up the pattern so that it can be used many times. The box maker uses in sequence: the pounce wheel; the knife; and the convex edge wheel.